use while (runTime.loop() { .. } where possible in solvers

- change system/controlDict to use functions {..} instead of functions (..);
  * This is internally more efficient
- fixed formatting of system/controlDict functions entry

- pedantic change: use 'return 0' instead of 'return(0)' in the applications,
  since return is a C/C++ keyword, not a function.

tutorials/basic/potentialFoam/cylinder/analyticalCylinder/analyticalCylinder.C

@@ -64,7 +64,7 @@ int main(int argc, char *argv[])
 
     Info<< "end" << endl;
 
-    return(0);
+    return 0;
 }
 
 // ************************************************************************* //